Automatic train control and signaling system



March 15, 1938. c. MODQNALD 2,110,960

AUTOMATIC TRAIN CONTROL AND SIGNALING SYSTEM Filed Dec. 28, 1936 3Sheets-Sheet 1 23m a \m wxuo'fi/ W i M March 15, 1938. J. c. MCDONALD2,110,960

AUTOMATIC TRAIN CONTROL AND SIGNALING SYSTEM Filed Dec. 28. 1956 3SheetsSheet 2 J l {9} Jaw/v C. Mwam AL March 15, 1938. J. c. M DONALDAUTOMATIC TRAIN CONTROL AND SIGNALING SYSTEM Filed Dec. 28, 1956 3Sheets-Sheet 5 HHHHH BLOCK JOHN G M fiO/VA L D 2114 I fl M Patented Mar.15, 1938 UNITED STATES AUTOMATIC TRAIN CONTROL AND SIGNAL- ING SYSTEMJohn 0. McDonald, New Yorlr, N. Y.

Application December 28, 1936, Serial No. 117,929

13 Claims.

My invention relates broadly to railway train control and signalingsystems, and more particu larly to an improved block arrangement andmethod of operation.

One of the objects of my invention is to provide a dependable andefficient method of signaling and controlling the operation of railwaytrains in an extensive block system, with simplifled apparatus andcircuit connections.

Another object of my invention is to provide a method of supplyingalternating current to a track circuit whereby various lengths of trackmay be accommodated with no substantial change in the application oroperation of the 16 system of my invention.

A further object of my invention is to provide a method of supplyingalternating current to signaling and control apparatusv in a railwayblock system for dependable and efilcient control there- 20 of by relayswitch devices.

Still another object of my invention is to provide a method of actuatingcontrol and signaling devices on a train, from wayside stations, bypneumatic pressure, whereby physical contact '25 with the moving trainis avoided and dependable and efllcient operation of the system isassured, regardless of the speed of the train.

Still another object of my invention is to provide a method of actuatingcontrol and signaling 30 devices on a train, from wayside stations, byradiant energy, whereby physical contact with the moving train isavoided and dependable and eflicient operation of the system is assured,regardless of the speed of the train.

35 A still further object of my invention is to provide an arrangementfor emergency control of trains in the block system of my invention inthe event of failure of the power supply of the system.

40 Still another object of my invention is to provide a constantindication in both block and cab signals of a clear track when suchcondition prevails, in combination with means for restricting the use ofcompressed air to a minimum.

45 A still further object of my invention is to provide means forsignaling at the wayside at the front end of any block, the entrance ofa train at the rear end of the block.

Still another object of my invention is to pro- !)0 vide service andemergency control of brakes on a train in accordance with trackconditions, in the block system of my invention.

Other and further objects of my invention reside in the circuitarrangements and methods of 55 operation hereinafter more fully setforth, with vention, shown in different positions; Fig. 6 is a modifiedform of track circuit for use in the system of my invention for speedcontrol in isolated 10 blocks; and Fig. 7 is a modified form of circuitactuating means employing light sources and photo-sensitive devices.

Railway block systems heretofore known have employed various devices forcommunication be- 15 tween a fast moving train and a wayside control andsignal station; such devices being either of the direct contact typewherein electrical circuits are positively completed through a directcurrent source of supply, or the inductive type in which electricalcircuits aboard the train are actuated by induced electromotive forcesfrom track or wayside apparatus fed with alternating current of highfrequency or distorted wave form. My invention employs alternatingcurrent from the standard power mains of the locality, applied to therails in such a manner that increase of the voltage is not required byextended rail sections,

nor is the voltage commutated at any point by relay contacts in such away as to produce sparking. Low voltages of low frequency may beemployed with entire satisfaction. The system of my invention employs anarrangement for actu ating the signal and control circuits aboard thetrain by means of compressed air expelled at wayside points under thecontrol of the block system, and adapted to actuate rocker arm switchmembers. In this manner, safety and dependability are assured, andapparatus essentially rugged inexpensive and simple, and easily main- 40tained, is employed.

Referring to the drawings; Fig. 1 shows the arrangement of the waysideapparatus in schematic form. It will be understood that the tracksections may be made of various lengths, and that connections to thetrack are made substantially as shown with respect to the separate blocksections, while the apparatus may be housed at any convenient location,preferably adjacent the track and power lines to facilitate servicing,and the compressed air tank and valves are positioned in the block at aselected point or points for effective coaction with the apparatuscarried by the train. In Fig. 1 it will be noted that the control systemis a single line, and that no other interconnection or intercoupling isemployed betzveen sections, except the common ground connection, whichmay be omitted when a common power supply system is employed.

On Fig. 1, I have designated blocks 1, 2, 3, and 4. Blocks 1 and 4 aremerely indicated, but blocks 2 and 3 are shown essentially, the controlfrom block 3 to block 2 to be fully set forth as an example of theoperation of the system for control of a train running through block 2towards block 3. Corresponding parts in the different blocks aredesignated by primed like reference characters in block 3.

Referring more particularly to block 3, voltage from power lines I isapplied to a step-down transformer 2', and from the secondary thereof,at low voltage to the primary 3c-32) of a 1:1 ratio transformer 3'through a reactor coil 4'. The secondary 3a'3c' of thertransformer 3'has one terminal thereof connected with one terminal of the primarywinding as at 3a, and the primary and secondary windings are arrangedwith the magnetic fields thereof in opposition, so that when thecurrents in the two coils are in the same phase, as when the otherterminals, 3b and 3c, of the windings are connected together, the fieldswill neutralize each other. When the currents are of different phase,however, as when suitable impedance is inserted between the terminals 3band 3c of the windings, a voltage appears across the impedance.Accordingly, in the system of my invention, the terminals 3c and 3b ofthe windings of transformer 3 are connected at the front end of a tracksection to respective rails 5' and 6, and to the rails at the rear endof the section is connected the actuating winding 1' of a relay switchdevice including a plurality of contact members and fixed contactsfor'cooperation therewith. The impedance represented in the winding 1'has a voltage thereacross suflicient to actuate the contact members andto hold the same in raised position. A short circuit across terminals31), 30', such as would be caused by a train in the block, would causethis voltage to disappear whereupon the relay contact members would bedropped. The fixed relay contacts control the operation of signal andcontrol apparatus in the block ahead as well as in the same block, aswill hereinafter be fully described. The current drawn from thesecondary of transformer 2 with terminals 3b and 3c short-circuited, issomewhat greater than the normal current due to the decreased impedancein the device 3, as a whole, under such conditions; but the current inthe rails is reduced to substantially zero by reason of theneutralization of the fields in the 1:1 ratio transformer which causesthe-voltage across the rails to disappear.

Referring now to block 2, connected to'the power lines I is a 1:1 ratiotransformer 8, connected like transformer 3, to provide a potentialdifference across impedance in series with the secondary winding. Theimpedance in this instance is found in the actuating coils of valverelease mechanisms 9 and I0 connected with a compressed air tank l2.Electromagnetic means for short circuiting this impedance is provided incontact members 14 and fixed contacts 15, controlled by an actuatingwinding l6 which is adapted to efiect quick break but slow make of thecontact members and contacts controlled thereby.

The actuating winding I5 is normally energized by power supplied fromthe lines I through two parallel switch elements, one controlled byrelay winding 1, and the other by relay winding 1. So long as the trackin block 3 is clear, the winding I6 is energized through contact memberl1 and fixed contact l8. With contact .member l1 dropped against deadcontact I8a', by the presence of a train in block 3, the operation ofthe winding I6 is controlled by the arm l9 and fixed contacts 20 and20a, controlled by relay winding 1 which is fed from the power lines Ithrough transformers 2 and 3 and tracks 5 and 6. The

'winding I6 is normally energized through contact 20 but upon entry of atrain in block 2, contact member i9 is dropped. The momentary break inthe circuit (contacts l1, l8 being considered open-by reason of'anadvance train'in block 3) causes the winding l6 to'release contactmember l4, thus opening the air valves 9 and ID by the operation of theactuating windings thereof through transformer 8. The power supplycircuit to winding I6 is immediately completed again through contact 20abut due to a time delay in the winding I6 which constitutes it a slowacting relay device, the contact members 14 will not be raised for theduration of a predetermined period, during which the train passes theopen valves and receives the pressure of the discharged air on suitableapparatus for controlling the operation of the train, as willhereinafter be described. With contact members l4 raised again, thevalves 9 and II) are closed, although the train may still be within theblock.

An additional air release valve 2| is provided on the tank H, with theactuating winding thereof connecteddirectly with the power lines I atall times. The valve 2| is constructed so that when energized, asnormally, air is confined, but when deenergized by failure of the powersupply, the valve 2! opens and air is discharged for controlling theoperation of passing trains.

Referring. now to Fig. 2 which shows schematically the connection of theapparatus in the cab of the train. An alternating current power supplyis indicated at 25, feeding the lines 26. A 1:1 ratio transformer v2| isconnected, like transformer 3' in Fig. 1, to provide a potentialdifference across impedance in series with the secondary winding. Theimpedance in this instance is found in reactor coils 28 and 29, seriesconnected. The voltage across reactor 28 is employed to energize theactuating winding 30 of a retarded relay device of the slow break, quickmake type, including contact members 3| and 32 and fixed contactscoacting therewith. The voltage across reactor 29 is employed toenergize the actuating winding 34 of a prompt acting relay device havinga contact member 35 and coating fixed contacts. Means for shortcircuiting the reactors 28 and 29 is provided in contact members 36 andfixed contacts 31, controlled by an actuating winding 38 in a relayswitch device which includes also contact members 39 and 40 and fixedcontacts coacting therewith.

Relay winding 38 is energized from the power source 25 through a switchmechanism 4|, shown more particularly in Figs. 3, 4, and 5, adapted tobe actuated by air pressure released through valves 9, l0 and 2| atwayside points and intercepted by the pivoted vane 42 on the switchmechanism II. In normal position, as shown, contact members 36, 39 and40 are dropped, and reactors 28 and 29 supply a potential drop towindings 30 and 34, respectively. Brake control valves 45 and 46 areprovided with release devices normally held closed by current from thesource 25. The actuating winding in valve 45 is connected throughcontact members 34 and ii in raised position; and the actuating windingin valve 46 is connected through contact member 32 in raised position.Contact member 35 is adapted to be dropped immediately upon theoperation of switch 4i by. an air blast from the wayside, and results inthe application of service brakes by means of valve 45 "to check thetrain speed.

Immediately upon the actuation of switch 4|, a connection in shunttherewith is made through contact member 39 in raised position therebyprolonging the energization of relay winding 38. Means for breaking thisshunt connection or holding circuit is provided in a push key 41 underthe control of the engineer of the train. If the shunt is maintained fora sumcient time period, the retarded relay device under control ofwinding ill will be dropped, resulting in the application of emergencybrakes by means of valve 46, to stop the train. The application of theemergency brakes may be forestalled by operation of push key 41,reenergizing windings 30 and 34, and the emergency brakes may bereleased by operation of a push button switch 48 to shunt the contactmember 32 and its coacting contact, completing the circuit to theactuating winding in valve 46 for closing the valve. While theapplication of the emergency brakes may thus be relieved from automaticcontrol, the same cannot be done with respect to the service brakes.

Referring to the switch device 4i as shown in Figs. 3, 4 and 5, a fixedcontact a is provided in the form of a semi-circular band. A pivotedsupport 43 is provided for mounting the vane 42 parallel to the track.The support 4| also carries contact members 4!!) and He projectingwithin the semi-circular band 4la, out of contact therewith in thenormal central position of the contact members maintained by virtue ofcoil spring elewinding 1, the contacts being closed with the contactmember 52' raised under conditions of clear track in block 3. A loadreactor 54 is provided in shunt with lamp 56. Under the same conditionsof clear track in block 3, contact member 56' closes a circuit throughcontact 51' and the actuating winding of an air release valve 58connected across the reactor 4 in the secondary circuit of powertransformer 2. The voltage drop across the reactor 4 is dependent uponthe current in the track circuit in block 2 and is small andinsuflicient to operate the valve 58 when block 2 is clear; but with atrain in the block, as shown at 60, creating a short circuit in thetrack, the current in reactor 4 is increased to a value sumcient tooperate the valve 58 which directs a Jet 01' air in a selectedhorizontal plane in the path of a train in block 2. If block 3 is notclear, contact member 56' is dropped and the circuit to valve 58 isopened.

A contact 53a engageable by contact arm 52' when dropped, is connectedin circuit with a reactor GI and a red lamp 62 across the power lines I.A load reactor 63 is provided in shunt with lamp 62. An air releasevalve 64 has an actuating winding connected in shunt with the reactor6|. Thus, the red lamp will be lit and the valve 64 opened when therelay winding I is deenergized by the presence of a train in block 3,the valve 84 operating to discharge a let air in an individual selectedhorizontal plane in the path oi a train in block 2.

Similarly, a contact arm 61' coacts with a contact 61a in droppedposition, to complete a v circuit from the power lines i through areactor 69 and a yellow lamp 10, with the load reactor II in shunt withlamp. An air release I! has an actuating winding connected in shunt withthe reactor 88. Thus, the yellow lamp will be lit and the valve I!opened by the presence 01 a train in block 3, the valve 12 alsooperating to discharge air in an individual selected horizontal plane inthe path of a train.

It will be noted that green lights will be showing in the block systemat all times when tracks are clear whereas in order to conserve energy,air is expelled for indicating a green signal in the cab 01'. a trainonly while the train is in any particular block. This has been describedas effected by means of the increased current in reactor 4 when thetrack circuit 5, 6. is short circuited as at 80. By virtue of thisfeature, a further indication may be had in the nature of a signal atthe front end 01' a block upon the entrance of a train at the rear. Thusa device such as a bell 13. or a blinker signal, connected in shunt withthe reactor 4, like the actuating winding of valve 58, will serve towarn road crews which may be working on the track of the approach oi. atrain. This system eliminates the use of special circuits for suchsignaling, as it is incorporated directly into the block system. Aswitch 14 may be employed to open the circuit in instances where thissignal is unnecessary orundesirable at all times.

Considering Fig. 2 again, and the cab circuits for actuating the signallamps, power from the source 25 is fed through separate 1:1 ratiotransformers I and 18, connected like transformer 3' in Fig. l toprovide potential drops across impedances in series with the secondarywindings of the transformers l5 and 18 respectively. The impedances arefound in relay windings I8 and 18, respectively, which control theoperation of a plurality of contact members and fixed coacting contacts.A switch mechanism 80, adapted to be actuated by the air jet from valveI2, is connected in shunt with the impedance of winding I9; and asimilar switch mechanism 8i, adapted to be actuated by air from valve64, is connected in shunt with the impedance of winding 18. Anotherswitch mechanism 82 is adapted to be actuated by air ejected from valve58. The switch mechanisms 80, 8| and 82 are identical in form to theswitch mechanism 4|, hereinbefore described, and, as indicated have acommon connection, together with switch 4|, to the grounded side of thepower source 26. As shown on Fig. 2, for indicating the cooperativerelation of the switch mechanisms with the wayside air valves, valves 9,l0 and 2| discharge in the same horizontal plane for actuating switchmechanism 4i; whereas valves 58, 84 and 12 are arranged to discharge inseparate horizontal planes for individually actuating switch mechanisms82, ill and 80 respectively.

As shown in Fig. 2 in accordance with circuit conditions indicated inFig. l, valve 58 is open and switch mechanism 82 is actuated. Thefunction of switch 82, in conjunction with a relay device having awinding 83 controlled by switch 88, is to restore the green signal inthe event other signals have been made. The circuits are shown inrestored relation, with a green signal lamp 88 energized from the powersource 28 through contact arms 88 and 81 and upper coacting contacts 88and 88, respectively. Contact arm 85 and another 88 are controlled byrelay winding 18; and contact arm 81 and another 81 are controlled byrelay winding 19.

Upon actuation of switch 80, relay winding 18 will be deenergized andcontact arm 81 will drop on contact 880, extinguishing green lamp andlighting a yellow lamp 8!. Contact arm 9| will also be dropped and willcomplete a circuit through contact Mo, to a relay winding 96, andthrough a contact arm 84 (dropped by relay winding 88, whendeenergized), and a contact arm 85 in dropped position, so that relaywinding 88 will be energized from the source 25. Contact arms 81 and 88are raised by relay winding 96,

a "holding circuit being completed through contact arm 91 and a contactarm I88, in dropped position, in shunt with the switch mechanism 80, sothat the yellow light will be maintained. The restoring action of switch82 and relay winding 88 breaks the shunt or holding" circuit throughcontact arm 81 by deenergizing winding 96 by raising contact arm 84.

Upon the actuation of switch 8|, relay winding 18 will be deenergizedand contact arm 85 will drop on contact 86a, extinguishing either greenor yellow light and energizing a red lamp llll. At the same time,contact arm 88 will drop on contact 88a and a circuit will be completedthrough a relay winding I02 and contact arms 40 and 88 when dropped byrelay windings 88 and 88 respectively. Contact arms I88, I03 and 88 willbe raised by winding I82, deenergizing relay 8! at contact arm 85,whereupon contact arm 98 drops on contact 88a so that a holding circuitmay be completed throughcontact arm 588, in shunt with switch mechanism8! to maintain the red light at illl. Contact arm I80 when raised, and81 when dropped, release the shunt on switch 88 so that relay winding 18raises the contact arms 8'! and 8|, which conditions the green lampcircuit for operation upon the clearance 01' the red signal. This iseffected as a result of the actuation of switch 4] which energizes relaywinding 88, thereby raising contact arm 48. At the same time that thered signal is extinguished however, brakes are applied and the trainspeed checked. Prior to the automatic application of the brakes theengineer, will be advised of block conditions by the red signal. The redsignal will also be extinguished by the re storing action of switch 82and relay winding 88, the circuit to relay winding I02 being opened whencontact arm 88 is raised. Relay winding Hi2, upon being deenergized atcontact arm 98 or at contact arm 48, drops the contact arms I I8, I83and 85, thereby releasing the shunt on switch 8i and permitting relaywinding 18 once again to raise contact arms 85 and 89, restoring thegreen lamp circuit. Thus the red signal may be extinguished without thebrakes having been automatically applied, and the train may resumespeed,

Referring to the system as a whole, and considering clear trafllc in theblock ahead, a train entering block 2, as at 80, will find conditions asshown in the drawings; that is, green lamp 88 will show lighted at thewayside, and valve 58 is opened by the entrance of the train in theblock, as described, so that the clear track signal may be shown in thecab by actuation of the restoring circuits through relay 83, and thelighting of lamp 84, if it be not already lighted. Valve 58 closes whenthe train leaves the block.

Considering now that the train has passed into block 3, creating acondition for block 2 of an occupied block ahead. Green lamp 50 in block2 is extinguished, red and yellow lamps 82 and ID are lighted and thecorresponding valves 84 and 12 are-opened, and the circuit to relay I8is opened through contacts ll, I8, all by the action of relay switch I.A train entering at the rear of block 2, as at 68, now will find cautionand danger signals. The yellow lamp 18, and valve 12 may be positionednear the entrance of the block, so that the engineer will be advised bywayside and cab signals to proceed with caution. And the red lamp 62 andvalve 84 may be positioned a predetermined dis tance from the exit ofthe block so that the engineer will be advised by wayside and cabsignals to stop. Furthermore, the brake control valves 9 and I areopened under these conditions and may be positioned adjacent or beyondthe stop signal 62 and valve 84 so that the brakes will automatically beapplied and the train stopped within the block. The emergencyapplication of brakes is an added safety measure and will occur ininstances where the engineer is not able to operate the controls.Normally, the emergency operation is forestalled by the use of switch 48and the train is stopped under the control of the engineer who mayoperate switch 81 to release the brakes and proceed when the block aheadis clear, as shown by the lighting of the wayside green lamp 511, whichmay be positioned at the entrance to the next block, block 3, withinwhich it is controlled. Yellow and red lamps are extinguished with thelighting of the green lamp 50, and in the cab, the green lamp is lightedagain by the opening of contacts 48 by relay 38 which releases relayI02.

The restoring action of switch 82 and relay 83 is taken advantage of bypositioning valve 58 at the wayside to be met by the train prior tovalves 9 and Ill, so that if the block ahead is clear before the trainreaches valves 8 and ill, the green lamp 84 in the cab will be lightedand .the engineer may resume speed immediately, and by holding switch 41open the operation of valves 8 and ill will not take effect. Duplicatesof any of the valves, particularly of valve 58, may be employed alongthe wayside, especially in very long blocks, so that clearance of theblock ahead may be promptly noticed in the cab.

The speed control system of my invention may be applied to isolatedblocks for controlling the speed of trains on bad roadbeds, bridges,curves, or grades, in the manner shown in Fig. 6. The power connectionsto the track include transformers 2 and 8" and the power take of! feedsa, relay winding 1 with an associated contact arm l9" and contacts 20"and 20a". A connection from l9" alone feeds a'relay winding of the slowacting type at l6" for controlling the operation of valves 9" and I0"fed from a transformer 8", all in a manner similar to that described inconnection with Fig. 1, with the exception of the control connection towinding II" from the track ahead. Thus, any train entering a block soprepared would be controlled in accordance with predetermined standardsand regardless of traflic conditions ahead.

till

tilt

Compressed air tanks it, fill, it", may be maintained with a pressure of100 pounds per square inch, for example, by an electric drivencompressor controlled by the tank pressure in a well known manner. Ventopenings of one inch diameter are satisfactory, with a clearance ofapproximately one-half inch from the enacting.

pivoted vane which may be recessed in the side of the train, 1

The lamps employed, particularly in the way side track system at to, $2,and it, are of the series type and operate by the potential drop acrossthe respective reactors 5 3, st, ll, in shunt therewith. lhese lampshave rugged filaments and operate on low voltage, and are entirelydependable.

In lieu of compressed air tanks and cooperating valves and vane switchmechanisms as described, ll may employ radiant energy and radiant energyit "pensive devices such as photoeelectric cells. l traclr system theair release valves may be :3 by light sources adapted to project lighttn-.5 track, wliile in the can system, photo sitive devices replace thevaneswitch mesh-- it, til, ill and t2, and are adapted to duct currentwhen light rays are intercepted on the photo-sensitive elements. Fig. 1indicates this modification of the system of my invention and showslamps ltd, W5, it'd, ill? and Edit to be controlled by track conditionsas hereinbefore described with regard to valves lit, t ll, it, ll andill, respectively. Lamp tilt, Fig. 1', may be ener glued from a separatepower source lit held connected by the relay device i it normallyenersized from the power lines l, the function oi lamp ltd being similarto that of valve El, both devices being actuated upon the failure of thepower supply for lines 9. In the cab system, photo-sensitive deviceslid, H5, lit and lit connected with a source of direct current potenthat] lit through relay devices tit, tilt, till, 522, respectively.Light falling on any oi the pliotosensitive devices willcause'enereiaation or the respective relay to close contacts connectedin the control and signal circuits as shown in 2. will be understoodthat the lamps and photo sensitive devices are correspondingly disposedin difierent horizontal planes similar to the ar rangeznent of airvalves and vanes shown in Figs. 1 and 2. Infra-red or like invisible maybe employed in the arrangement shown in Fig. l in order to increase theselectivity and dependability of the system.

While X have thus described my invention in certain preferredembodiments, I desire it understood that no limitations upon myinvention are intended, and that modifications may be made such as arewithin the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is as follows:

1. in a railway bloclr system including the rails of a track: sectionfor passage oi a train there over, a source of alternating current; a1:1 ratio transformer having first and second windings arranged inopposition, said first winding con nected directly across said sourceand at one end to a track rail, said second winding connected to theother end of said first winding and to the other traclr rail, and animpedance device con" nected across the track rails and consequently inseries with said second winding; whereby normally the track rails areenergized by a voltage resulting from phase shift in the magnetic fieldof said transformer due to said series connected impedance device andwith the rails shunted by a train the output from the transformer to therails is substantially zero.

2. In a railway block system, the arrangement set forth in claim 1wherein said impedance device comprlses the inductive actuating windingof a relay switch device having control means operable thereby forselectively transmitting control energy to a train in said tracksection, said relay switch device being actuated by the presence of atrain in said track section which substantially shunts the inductiveactuating Winding of said device.

3. In a railway block system, means for controlling a train enteringsucceeding sections in a. series of track sections, comprising means forsupplying electric control energy to the track in each section, relayswitch. means connected with each track section and normally energizedtherefrom, said relay switch means including a plurality of cooperativecontact elements; a relay device and control means adapted to beactuated thereby in each track section; and means includtiny cooperativecontact elements controlled bythe relay switch means in a succeedingsection for conditioning relay device in the adjacent preceding sectionfor actuation by the relay switch means in the said preceding section,and means including cooperative contacts controlled by the relay switchmeans in the said. preceding section for actuating the relay device inthe same section.

i. In a railway 'nloclr system, means for con trolling a train in aseries of track sections as set forth in claim and wherein said relaydevice is of the qlllCiii-blfidk, slow -maize type actuated by relayswitch contact elements so connected and arranged as to restore thecircuit through sail. relay device immediately upon the actuationthereof.

ii. In a train control system, means for autoniatically actuating traincarried control apparates comprising a source of alternating current, a1:1 ratio transformer having first and second windings, said flrstwinding connected directly said source, a reactor connected with one endof each of said flrst and second windings, the other ends of saidwindings being connected together, said reactor being in series withsaid secand winding across said source, whereby normally said reactor isenergized by a voltage resulting from phase shift in the magnetic fieldof said transformer due to said series connected reactor; relay switchmeans including a. plurality of contact elements certain of which areconnected in shunt with said reactor, a relay device energized by thepotential drop normally across said -reactor and adapted to actuate saidtrain control apparatus, and-means operable in accordance with trafilcconditions in the system for energizing said relay switch means foractuating said relay device, the output from said transformer to thereactor being substantially zero with said shunt contact elements closedby the operation of said relay switch means.

6., in a train control system, means for autornatically actuating traincontrol apparatus, which comprises a source of alternating current,relay switch means including a plurality of contact elements, a pair ofrelay devices energized from said source and adapted to be controlled bybreak, quick-make type, a vane type switch operable to energize saidrelay switch means for actuating said relay devices, and actuating meansfor said vane type switch comprising wayside pneumatic devices operablein accordance with trafilc conditions in the system.

7. In a railway block signal system, means for signaling a trainentering succeeding sections in a series of track sections comprisingmeans for supplying electric control energy to the track in eachsection, relay switch means connected with each track section andnormally energized therefrom, said relay switch means including aplurality of cooperative contact elements; signal lamps associated witheach track section, means including normally closed contact elementscontrolled by the relay switch means in a succeeding section forenergizing one of said lamps in an adjacent preceding section, meansincluding normally open contact elements controlled by the relay switchmeans in said succeeding section for energizing others of said lamps insaid preceding section, said relay switch means being actuated by thepresence of a train in the associated succeeding track section.

8. In a railway block signal system, means for signaling a train in aseries of track sections as set forth in claim6 and including controldevices electrically connected with the last mentioned lamps andactuated in conjunction therewith for transmitting the signal indicationto a train in the associated section, and a control device arranged foroperation in accordance with the condition of the first mentioned lamp,and means for actuating the last said control device by a train in theassociated section for transmitting a signal indication to said train.

9. In a relay block system, the arrangement set forth in claim 1 andincluding signal means connected in series with the said first windingof said transformer across the source of alternating current; said meansbeing inoperative under current conditions in the said first windingwith said rails energized from said transformer, and operative underincreased current conditions in said first winding with the railsshunted by a train for signaling ahead in said section the presence of atrain in said section.

,10. In a train signal system, meansfor automatically actuating signaldevices on a train, which comprise a source of alternating current,relaydevices energized from said source and cooperative for controllingsaid signal devices, a plurality of relay switch means, and a pluralityof vane type switch devices actuated by wayside pneumatic means operablein accordance with traflic conditions in the system for controlling theoperation of said relay devices, said relay switch means being operativeupon the actuation of said vane type switch devices to maintain theeffect of said switch devices.

11. In a train signal system, means for automatically actuating signaldevices on a train, which comprise a source of alternating current,relay devices energized from said source and cooperative for controllingsaid signal devices, a plurality of relay switch means, and a pluralityof vane type switch devices actuated by wayside pneumatic means operablein accordance with traffic conditions in the system for controllingsulated from each other, means for supplying energy to the track in eachblock, a relay device for each block energized through the track in therespective block, contact means controlled by the individual relaydevices and operative to actuate signal and control devices inrespectively adjacent blocks, said signal and control devices includingpneumatic pressure release valves on the way-. side in the respectiveblock, and pressure responsive devices on a train operable in saidblock.

13. In a railway train control system, actuating means on the waysidecomprising a compressed air storage tank and a plurality of air releasevalves connected therewith each having an electrically operatedactuating device, said air valves being disposed in different selectedhorizontal planes and operative to project air jets normal to thetracks; and a plurality of switch mechanisms carried by a moving trainin corresponding selected horizontal planes and in positions to beactuated by the respective air jets from the wayside actuating means,the operation of said air release valves being selectively controlled inaccordance with the trafilc conditions in said system.

JOHN C. MCDONALD.

